Dry yeast and method for producing the same



Patented Sept. 6,. 1927.

. UNITED STATES PATENT OFFICE.

CHARLES B. HILL, OF GLENCOE, AND MAURICE H. GIVENS, F EVANSTON, ILLINOIS,

ASSIGNORS TO NORTHWESTERN YEAST COMPANY, OF CHICAGO, ILLINOIS, ACOR- IPORATION OF ILLINOIS.

DRY YEAST AND METHOD FOR PRODUCING THE SAME.

1N0 Drawing.

This invention relates to a novel process, hitherto unknown, for growing yeast and drying it so that the resultant yeast product has an increased raising and fermenting 6 power, when used for bread making,the

term dry yeast meaning a product containing yeast cells, in the presence of organic and inorganic substances, dehydrated so that the moisture content lies between eight (8) 19 and fourteen (let) per cent.

The objects of this invention are: to produce a dry yeast of high cell content and special composition in which the yeast cells are prenourished before partial dehydration,

thereby storing up food within their walls to better withstand the deleterious effect of drying; to furnish the yeast with yeast nourishing, inorganic salts on which to so feed both before and after drying; to limit 20 the use of the inorganic salts during the initial growing of the yeast so that While an acid reaction unfavorable to the yeast will be prevented, one inimical to bacteria established during the drying of the yeast and also later in the making of dough is produced.

The invention consists in economically and cheaply attaining the foregoing and other objects, thereby producing a product'and using a process which differs materially from the well known dried yeasts of the prior art and their manners of production. More specifically, the invention consists in giving yeast cells inorganic salts to feed on,

stopping the feeding before the total quantity of salts is consumed whereby the yeast and the unconsumed parts of the salts viz, derivatives, as well as unconsumed salts are carried together to market in such a condition that the feeding operation can be and is resumed when the yeast is set to leavening. The invention further consists in details and features more fully set forth in the specification and claims.

The dried yeast of this invention can be used in commercial baking, Whereas heretofore it has not been profitable for the baker to use such a type of leavening agent. To the commercial baker, the use of this invention means a savin in time and labor; eliminates the necessityfor the usual yeast foods and produces a better bread with a more palatable crust and enlarged final loaf volume. With the yeast of this invention,

Application filed March 4, 1926. Serial No. 92,331.

there is no requirement for cold storage, as with compressed and wet yeasts, and hence 1ts easy handling is facilitated.

The following is an example of the manner 1n which the process of this invention may be carried out:

To 1.5 lbs. dry yeast, as, for instance, the commercial product known as yeast foam, 1n a suitable container, add 0.03 lb. salt, 0.12 lb. sugar and 3.75 lbs. water' at 90 degrees F., mix and let stand 3 hours. While mlx ng, add slowly 1.36 lbs. rye flour and agaln let stand at a temperature of 80-85 degrees F. for 3 hours. For convenience, call this completed mixture A. 4

Into 8.5 lbs. boiling Water drop .04lbs. hops, enclosed in a cheesecloth bag, and mamtain the boiling for one-half hour. Remove the hop bag and add boiling Water to make up to original volume. To this hot hops extract addwith stirring2.72 lbs. corn meal and then cover and let stand 5 minutes. Now stir into this mixture 2.72 lbs. rye flour, 7.55 lbs. water and .7 lbs. commercial malt extract. Let this entire mixture stand until temperature falls to 95 degrees F. and then stir into it mixture A. Let the whole stand for 1% hours at a temperature of 80 to 90 degrees F. and then thoroughly stir in .04 lbs. salt. For conyellgn ence, designate this completed mixture Place all of B 7 in amechanical mixer and, after some little preliminary'stirring,

incorporate 7% lbs. rye flour and 8.5 lbs.

water at .a temperature of 80-85 degrees F. Now add, with mixing, 16% lbs. corn meal and let stand for 2 hours at 80 to 90 degrees F. This completed mixture is, for convenience, designated C To 12.00 lbs. of corn meal, add yeast nourishing, inorganic salts, specifically 1.9 lbs. of ammonium sulphate (NH,) SO,,, 0.94 lbs. of calcium phosphate Ca (PO and 0.94 lbs. of calcium sulphate, CaSO, 2H O and thoroughly mix these substances. Call this D. 4

When 0 has stood for the time indicated thoroughly mix D into it and roll the whole out into a dough and cut into desired size cakes. During this mixing, the yeast in C starts to feed on the inorganic salts. of D and this continues during the earl stages of the drying hereafter describe usually used in baking and letting the mixture stand at to 90 degrees F. for 15 hours, when it can be used in lieu of any so-called compressed yeast.

The foregoing description gives a typical procedure, but it is evident and is to be understood that the whole operation includes variable elements and hence the details of procedure may be widely varied, without departure from the spirit of the invention or the scope of the subjoined claims. Attention is called to these facts: namely, there is variation in the moisture content of grains and there is variation in the growing and fermenting ability of different species of yeasts.

The moisture is so regulated in the dough from D that, during the subsequent and final drying, the yeast uses part only of the inorganic salts and leaves a remainder for its further use, when water is added to it to make the final yeast starter for making bread dough. The yeast, in using part of the inorganic salts,stores up in itscells some of the inorganic radicals, so that it can better withstand the deleterious effect of dehydrating and, further, it produces, by its use, other inorganic substances or derivatives, as, for example, sulphuric acid, which is inimical to bacterial growth, but, in the amount here permitted to be formed, is not injurious to the yeast nor preventive of yeast growth. There are also other biochemical reactions occurring, which can now be recognized by those familiar with the science and trade of yeast growing. It is self-evident now how the process of this invention differs from any already disclosed or known because in these latter cases, the inorganic salts have been used, as a rule, for growing yeast in clear wort and any unconsumed, inorganic salts, together with the secondary products formed by the action of the yeast on the inorganic salts, have always been removed from the yeast before its use or preservation. By the term malt is meant either ground malted grains in any form, or any extract thereof.

As many changes could be made in carrying out the above method, even to adding other substances,- as spices and flavoring extracts, without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

In drying the final product, 80 to 90 degrees F. are best but 60 to- 100 may be used.

Attention is called to the fact that the partial consumption only of the inorganic salts is controlled in two ways: (a) by drying; and (b) by inserting the salts so late in. the operation described that the yeast does not have time to consume all the salts before drying starts. That is tosay, if the salts were fed in early in the process, they would be so far as feeding is concerned entirely consumed by the yeast before the drying starts.

It is desirable to use a mixture of inorganic salts, but a single one may be used without entirely destroying the invention.

By inorganic salts is meant, at all points in the specification and claims, those which are suitable, to nourish yeast. The use, generically of a composition of matter composed of ammonium sulphate, calcium sulphate, calcium phosphate (Ca,(PO,) in bread making is set forth and claimed in our companion application Serial No. 160,- 299 filed January 10, 1927.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. The process which comprises growing yeast in the presence of malt on predetermined quantities of ground cereals and a yeast nourishing, inorganic salt, and stopping the action of the yeast on the inorganic salt prior to its complete consumption by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed, inorganic salt and derivatives thereof, ready for feeding the yeast when the yeast is used in leavening operations.

2. The process which comprises growing yeast in the presence of malt and sugar, on predetermined quantities of ground cereals and a yeast nourishing, inorganic salt, and stopping the action of the yeast on the inorganic salt prior to its complete consumption by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed,

inorganic salt and derivatives thereof, ready ganic salt, and stopping the action of the yeast on the inorganic salt prior to its complete consumption by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed, inorganic salt and derivatives thereof, ready for feedingthe yeast when the yeast is used in leavening operations.

5. The process which comprises growing yeast in the presence of malt on predetermined quantities of ground cereals and yeast nourishing, inorganic salts, stopping the action of the yeast on the inorganic salts prior to their complete consumption by the yeast,

whereby the yeast thenceforth carries associated with it said unconsumed, inorganic salts and derivatives thereof, ready for feeding the yeast when the yeast is used in leavening operations.

6. The process which comprises growing yeast in the presence of malt and sugar, on predetermined quantities of ground cereals and yeast nourishing, inorganic salts, stopping the action of the yeast on the inorganic salts. prior to their complete consumption by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed, inorganic salts and derivatives thereof, ready for feeding the yeast when the yeast is used in leavening operations.

' 7. The process which comprises growing yeast in the presence of malt, sugar and hop water, on predetermined quantities of ground cereals and yeast nourishing, inorganic salts, stopping the action of the yeast on the inorganic salts prior to their complete consumption by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed, inorganic salts and derivatives thereof, ready for feeding the yeast when the yeast is used in leavening operations.

8. The process which comprises growing yeast in the presence of malt and hop water,

on predetermined quantities of ground cere-- als and yeast nourishing inorganic salts, stopping the action of the yeast on the inor ganic salts prior to their complete consumption by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed inorganic salts and derivatives thereof, ready for feeding the yeast when the yeast is used in leavening operations.

9. The process which comprises'growing yeast on rye flour and corn meal in the presence of sugar, malt extract, hop water, sodium chloride, ammonium sulphate, calcium phosphate, calcium sulphate, stopping the action of the yeast on these inorganic salts prior to their complete consumption by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed inorganic salts and derivatives thereof, ready for feeding the yeast when the yeast is used in leavening operations, and drying. 10. The process which comprises growing yeast on rye flour and corn meal in the presence of sugar, malt extract, hop water and inorganic salts, stopping the action of the yeast on these inorganic salts prior to their complete consumption by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed inorganic salts and derivatives thereof, ready for feeding the yeast when the yeast is used in leavening operations and drying resultant product, prior to exhaustion of the salts, at a temperature-of 80 to degrees F. to a moisture content of less than 14 per cent.

11. The process which comprises growing yeast on rye flour and corn meal in the presence of sugar, malt extract, hop water, so-

dium chloride, ammonium sulphate, calcium phosphate and calcium sulphate, stopping the action of the yeast on these inorganic salts prior to their complete consumptlon by the yeast, whereby the yeast thenceforth carries associated with it said unconsumed inorganic salts and derivatives thereof, ready for feeding the yeast when the yeast is used in leavening operations, and drying the resultant product at a temperature of 80 to 90 degrees F. to a moisture content of less than 14 per cent.

12. A dried yeast product consisting essentially of live yeast cells, ground cereals, and ammonium sulphate, calcium sulphate, calcium phosphate (CA (PO and radicals split ofi from these salts with a moisture content of less than 14 per cent.

In witness whereof, we have hereunto subscribed our names.

CHARLES B. HILL. MAURICE H. GIVENS. 

